Summary

motor mount for attaching three bottle rocket motors to a small balsa glider

Instructions

A creative cousin of mine came to the family Christmas dinner bearing strange gifts. He handed out packages that contained balsa gliders, a roll of electrical tape, and a pack of bottle rockets! Fun and chaos immediately followed :) After several explosive flights using tape, I decided to give sketchup and the makerbot a go. Positioning multiple rocket motors just above the CG seems to balance the lift with a forward pitching moment and results in a nice and shallow powered climb followed by a long glide back to earth.

Step 1) Print a motor mount.

Step 2) Slide the mount to the top of your balsa glider.

Step 3) Strip down three bottle rockets. If they are the kind that "report" or explode after firing, you will want to modify this feature. Otherwise, the bracket will tend to disappear after first flight. I used a pair of pliers to squeeze the top 1/2 inch or so, breaking up the chalky cap. Tap and pour out the capping material until you see gray powder. Next, tape over the hole to prevent more powder from escaping. Now the report will be a small pop and no damage will occur to the plane or mount.

Step 4) Clip your modified rocket motors into the mount and adjust the CG. Twist the outer fuses over the base of the inner motor fuse to create a delay between the three motor firings. Adjust the center of gravity (CG) by moving the clip forward or aft, or by sliding the wings forward or aft. Test the CG by balancing the plane with your fingers at each wing tip, so that it can rotate nose up or down. You will want to adjust so that the CG is slightly forward of the center of lift, which means the nose should rotate down. Apply some transparent tape to keep everything from sliding around.

That's it! Light and toss into the breeze. Try different CG's and experiment with the toss and timing. I wanted to try some launch rails but ran out of bottle rockets. See video below for my results.

http://www.youtube.com/embed/-RHJIiawhlM

Bottle Rocket Motor Mount for Balsa Plane

Bottle Rocket Motor Mount for Balsa Plane

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